Abstract

Non-invasive ventilation (NIV) supports breathing without endotracheal intubation, lowering the risk of airway injury, sedation-related instability, hospital-acquired infections, and ventilator-associated complications. Growth in publications accelerated during and after the coronavirus disease-2019 (COVID-19) pandemic, yet regional representation of evidence remains uneven. Bibliometric synthesis is useful to clarify research structure, influence, collaboration intensity, and unmet scientific priorities in pediatric NIV. To analyze global publication trends, thematic clusters, and research-collaboration networks in pediatric NIV literature from 2013 to 2023. A systematic search of Scopus metadata was performed on July 23, 2024, using TITLE-ABS-KEY (non-invasive AND mechanical AND ventilation AND pediatric) and restricted to English-language publications (2013-2023). A total of 358 records were analyzed using Scopus analytics to assess annual output, author and institutional productivity, country contributions, keyword co-occurrence, and international co-authorship mapping. Frequently cited studies underwent a narrative review to provide clinical-translational context. Of the 358 documents, 276 (77.1%) were research articles and 55 (14.4%) were reviews. Publication output fluctuated between 2013 and 2018, followed by a steep and sustained rise from 2019 to 2023. The most prolific countries were the United States, Canada, and Spain, whereas Southeast Asia contributed a smaller share, highlighting opportunities for expansion in that region. Highly productive authors included Emeriaud G., Jouvet P., and Essouri S. Four major keyword clusters were identified: respiratory insufficiency, mechanical ventilation, continuous positive airway pressure (CPAP)/bronchiolitis, and acute respiratory distress syndrome/extubation failure. Overlay mapping revealed an increasing interest in CPAP, weaning/extubation outcomes, viral infection (COVID-19), and mortality-related metrics from 2020 to 2023. Pediatric NIV research is expanding, evolving from neonatal oxygenation and interface topics toward broader prognostication, de-escalation safety, and hard clinical outcomes. Underrepresented regions, including Southeast Asia, present clear potential for collaborative research. Future work should standardize criteria for early NIV success and failure and directly compare high-flow nasal cannula with CPAP/non-invasive positive pressure ventilation across diverse pediatric settings.

Introduction

Non-invasive ventilation (NIV) is a form of respiratory support provided without direct tracheal intubation. This avoids some complications inherent in invasive ventilation, such as the need for sedation with associated hemodynamic instability, delirium, and nosocomial infections.¹ NIV is primarily indicated for patients with mild-to-moderate acute respiratory failure and has been shown to be more effective than conventional oxygen therapy in selected patient populations.²

Research related to NIV in children has seen significant advancements in recent decades. The purpose of this study is to analyze publication patterns and collaboration among researchers and institutions, and to identify research trends and directions at NIV from 2013 to 2023. Performing a bibliometric analysis is expected to provide a comprehensive understanding of NIV research, enabling healthcare policymakers to make more informed and effective decisions.

Materials and Methods

Scopus searches were conducted on July 23, 2024, to collect basic publication and citation data from article titles, abstracts, and keywords. Scopus search query as executed, including the complete TITLE-ABS-KEY syntax, publication year limits, language restrictions, and keyword filters applied. The search terms used were (non-invasive AND mechanical AND ventilation AND paediatric); the full search string was: TITLE-ABS-KEY (non-invasive AND mechanical AND ventilation AND paediatric) AND PUBYEAR >2012 AND PUBYEAR <2024 AND [LIMIT-TO (LANGUAGE, “English”)] AND [LIMIT-TO (EXACTKEYWORD, “Non-invasive ventilation”)]. The search was limited to English-language publications and to the publication period 2013-2023. A total of 358 articles were exported as CSV files. Scopus’ analyze results, VOSviewer 1.6.19, and Biblioshiny were used to visualize and analyze occurrences of words and phrases in the titles and keywords of all retrieved articles.

The minimum occurrence of the author’s keywords is set at 10. The cluster of co-occurring events is represented by various colours, as indicated by the co-occurrence analysis of the authors’ keywords. The frame size corresponds to the appearance of the keywords. Its thickness is proportional to the intensity of the event. Yellow keywords appear in later years (2021 or later) compared with blue keywords (2018 or earlier), as shown in the overlay visualization. Density visualization depicts each term’s density; greater thickness indicates higher density. We conducted a literature review of the most-cited publications to gain a deeper understanding of NIV in children.

Results

Of 358 documents, 276 (77.1%) were articles and 55 (14.4%) were reviews (Figure 1). The trend in NIV research publications shows significant fluctuations from 2013 to 2018, followed by a marked increase from 2019 to 2023 (Figure 2). Research development prior to 2020 was limited, possibly owing to constrained research funding or alternative research priorities in child health. Meanwhile, the sharp between 2020 and 2021 was most likely attributable to coronavirus disease-2019 (COVID-19), rendering invasive and non-invasive mechanical ventilators a highly relevant research topic, as they were in high demand.

The countries with the highest number of publications are predominantly developed nations with better healthcare infrastructure and greater access to advanced technologies, led by the United States (124 articles), followed by Canada (43) and Spain (39) (Figure 3). Among the 10 countries with the highest number of publications, only one-India- is from Asia. This indicates limited research from Asia and Southeast Asia, presenting an opportunity for further investigation of NIV in the region. The most productive author on NIV is Emeriaud G., with 17 articles; this is followed by Jouvet P. (12 articles) and Essouri S. (11 articles). Other productive authors include Rotta AT., Shein SL., Abu-Sultaneh S., Kneyber, MCJ., Conti G., Blackwood B., and Fauroux B. (Figure 3). This can be an opportunity for these productive writers and researchers in various countries to collaborate, thereby expanding the scope of research in this field.

The ten most-cited articles are described in Table 1; seven of the ten concern pediatric cases. The most-cited article is “acute respiratory distress syndrome (ARDS)” by Matthay et al.³ with 822 citations. Followed by “non-invasive versus invasive respiratory support in preterm infants at birth: systematic review and meta-analysis” by Schmölzer et al.⁴ with 417 citations, and “paediatric acute respiratory distress syndrome incidence and epidemiology (PARDIE): an international, observational study” by Khemani et al.⁵ with 248 citations.

Co-occurrence Cluster

Co-occurrence network analysis of author keywords identified four thematic groups, comprising a total of 28 keywords (Figure 4). The densest keyword was NIV. The four research clusters were respiratory insufficiency, mechanical ventilation, continuous positive airway pressure (CPAP), and ARDS. The overlay visualization showed increasing interest in “extubation failure, CPAP, COVID-19, and mortality” (Figure 4A). The overlay visualization highlights emerging themes such as COVID-19 and mortality, as illustrated in Figure 4B. Most research on NIV using density visualization focuses on NIV, mechanical ventilation, children, pediatrics, COVID-19, and bronchiolitis (Figure 4C). This can be indicated by the bright yellow color. On the other hand, research on NIV is still limited in areas such as weaning, extubation, respiratory insufficiency, pediatric critical care, ARDS, and extubation failure, among others. Thus, addressing these items (Figure 4C) opens opportunities for further research.

NIV in the paediatric population has a wide spectrum of applications, from the prevention and early management of respiratory distress in neonates and therapeutic bridging in paediatric ARDS to postoperative support and long-term home ventilation in children with neuromuscular diseases. The synthesis of ten collected journal publications describes the developmental trajectory of evidence and clinical practice from 2013 to 2023, highlighting benefits, limitations, and open research directions (Tables 1-3).^3-12

A new term that emerged in 2022-2023 is “artificial ventilation”. Artificial ventilation, or mechanical ventilation, is a term used for any method that mechanically assists or replaces spontaneous breathing. This includes invasive methods (such as intubation and mechanical ventilation) and non-invasive methods (such as NIV). The primary goal is to ensure adequate gas exchange and oxygenation in patients who cannot breathe effectively on their own.¹³ Artificial ventilation and NIV are used to manage respiratory failure but are indicated in different clinical scenarios. NIV is often preferred for patients with acute or chronic respiratory diseases or those with mild-to-moderate respiratory disorders because it is associated with fewer complications than invasive ventilation. Although artificial ventilation and NIV both aim to support patients with respiratory failure, they differ in their application, patient comfort, and potential complications.^{14, 15}

In neonates, particularly premature infants with RDS, recent evidence confirms that NIV, especially CPAP and non-invasive positive pressure ventilation (s)(NIPPV), is the recommended initial respiratory support from birth.⁷ The latest European guidelines indicate that (s)NIPPV is the most effective primary therapy, while HFNC can be considered for stable infants, provided that CPAP/NIPPV is available as a backup option in case of failure. Seven meta-analyses comparing early CPAP with intubation in very preterm infants showed reductions in the need for mechanical ventilation and surfactant use, and an improvement in the combined outcome of mortality and bronchopulmonary dysplasia.¹⁰ From a bibliometric perspective, the topic of early CPAP and NIPPV for preterm RDS has become one of the main clusters, exhibiting a high publication rate and supported by strong evidence demonstrating significant clinical benefits, including reduced need for intubation and lower risk of long-term respiratory complications.^{7, 10}

In children with PARDS, the international PARDIE cohort study [27 countries; 145 pediatric intensive care unit (PICUs)] confirmed that both diagnosis and severity of PARDS can be determined using the PaO₂/FiO₂ and SpO₂/FiO₂ (PF/SF) ratio, even when the patient has not yet been intubated.^{5, 15} Degrees of hypoxemia have been shown to correlate with poor outcomes, and metrics such as ventilator-free days are now consistently used to compare outcomes for both NIV and IMV.¹⁵ In cases of early hypoxemic respiratory failure, evidence in the adult population suggests that high-flow nasal cannula (HFNC) reduces intubation rates and mortality compared with conventional oxygen; this finding has potential implications for pediatric patients with similar conditions.^{3, 15}

The key successful NIV in mild-to-moderate PARDS is thorough initial assessment, the selection of the appropriate modality (CPAP/NIPPV versus HFNC), and rigorous monitoring of oxygenation indicators (PF/SF).^3.15 The paediatric mechanical ventilation consensus conference (PEMVECC) (2017) recommendations suggest considering NIV for patients with obstructive and restrictive diseases, mild-to-moderate PARDS, cardiorespiratory failure, post-cardiac surgery, asthma, and neuromuscular disorders, with strict evaluation within the first hour to assess success.⁷ NIV should not delay intubation if failure criteria are met; selecting an interface that minimizes leakage is crucial.^{12, 16} In a cohort of patients undergoing congenital heart surgery, the need for preoperative ventilation, including NIV, was shown to correlate with delayed postoperative extubation. This indicates that NIV is not only a respiratory support tool but also a clinical marker of disease severity relevant to anesthesia planning and ICU management.^{12, 16}

The long-term use of mechanical ventilation in children continues to increase significantly, as evidenced by Canadian data (1991-2011), which recorded that 83% of patients were using NIPPV, primarily children with neuromuscular diseases, most of whom were treated at home. Studies in Spain during the COVID-19 pandemic also showed a shift toward younger populations, with increased use of NIV and a decrease in the need for invasive ventilation, length of stay, and mortality. Nevertheless, the cases of adolescents with severe multisystem disease confirm the limitations of NIV effectiveness when complex comorbidities are present.^{6, 10, 17} Implementing a rapid response system in a tertiary children’s hospital has been shown to reduce the incidence of critical deterioration by 62%, which demonstrates that early detection and rapid intervention play an important role in preventing severe respiratory failure.^{9, 18} Overall, evidence from the past decade confirms NIV as an effective strategy for preventing intubation in selected cases, such as neonatal RDS, mild-to-moderate PARDS, obstructive and neuromuscular diseases, provided that an initial assessment is performed, oxygenation indicators (PF/SF) are monitored, and a quick decision is made for intubation if NIV fails.^{5, 19}

A bibliometric analysis shows that research on NIV in children is dominated by four clusters: mechanical ventilation, critical care, CPAP/bronchiolitis, and ARDS/extubation failure. The keywords “NIV” and “mechanical ventilation” serve as network hubs, indicating their position as core themes connecting various fields such as neonatology, intensive care, and acute respiratory failure. Between 2013 and 2023, research focus shifted from the application of CPAP/NIPPV in neonates to advanced clinical issues such as weaning, extubation failure, COVID-19, and mortality. There appears to be an increase in the number of new topics after 2019, indicating that the pandemic influenced the expansion of the scope of NIV in children. Overall, this bibliometric analysis indicates that research on NIV is becoming increasingly multidisciplinary, evolving from technical aspects toward the assessment of clinical outcomes and patient safety, and facilitating cross-sectoral research collaborations, particularly in the fields of pediatric critical care and extubation outcomes.

Conclusion

A comprehensive review of non-invasive mechanical ventilation in children has been conducted. Research on non-invasive mechanical ventilation experienced fluctuations from 2013 to 2018, and then increased from 2019 to 2023. Rapidly growing numbers of publications originate from the United States, Canada, and Spain, while contributions from Southeast Asia remain limited. Future research is expected to focus on several important topics such as weaning, extubation outcomes, and pediatric critical care. External clinical evaluation and patient safety are also important topics that require further study to strengthen clinical practice and evidence-based policies.